Control relay and valve



2 Sheets-Sheet 1 a mm 5 GA F@ m.\ 2 \mm mm mm Aug. 25, 1964 Flled Aprll 11 1961 Aug. 25, 1964 R. HASSA CONTROL RELAY-AND VALVE 2 shets-sneez 2 Filed April 11, 1961 lngaziovr United States Patent Office 3,145,762 Patented Aug. 25, 1964 3,145,762 CONTROL RELAY AND VALVE Richard Hassa, Qsnahruck, Germany, assignor to G. Kromschroder Aktiengesellschaft, Osnabruch, Germany Filed Apr. 11, 1961, Ser. No. 102,273 Claims priority, application Germany Apr. 16, 1960 7 Claims. (Cl. 158-123) This invention relates to electrically operated fully automatic flame protection devices in which a pilot or main burner flame acts on one or more thermocouple elements to produce a change in potential or in current, which oper ates a relay in such a way that when the pilot or main burner flame is not burning it causes via an auxiliary circuit an ignition process and keeps the main gas valve closed; but when the said flame is burning it stops the ignition process and opens and keeps open the main gas valve, whereby the relay, automatically and directly and without any kind of amplifier or other intermediary, controls two auxiliary circuits, in one of which is the ignition transformer and in the other is the main gas valve.

An object of the invention is to improve such flame protection devices, in particular to prevent any unburned gas passing to the main burner, while an electric current remains until the thermocouple element has cooled down, and which could lead to blow out or explosion on ignition being restored. To avoid this, the invention provides in circuit with the thermoelectric relay a monitoring relay which, when there is a lack of current in the auxiliary circuit, not only closes the main gas valve, which preferably is magnetic but also, after removal of the cause of current interruption in the auxiliary circuit, keeps it closed until the ignition process has been restarted and has restored the thermoelectric current to actuate the thermoelectric relay and reopen the main gas valve.

An essential simplification of the flame protection device consists, according to the invention, in the pilot gas valve being controlled mechanically by the monitoring relay in such a way that, as the pilot flame is reestablished, the restoration of thermoelectric current brings the thermoelectric relay again into its operating position, thereby energizing the one auxiliary circuit, reopening the main gas valve and at the same time switching oh" the auxiliary circuit for the ignition transformer, while, as the ignition process recommences, both the thermoelectric relay and the main gas valve return to their other end settings. The monitoring relay and the pilot gas valve thus form a constructional unit and commerically available relays can be used.

A further object of the invention is the provision of a pilot gas valve directly coupled to the monitoring relay.

A further improvement of the flame protection device consists, according to the invention, in the monitoring relay and the electromagnetic main gas valve being arranged in the direct current circuit from an alternating current rectifier. It is a well-known fact that relays operated by direct current can function with greater voltage variations than those operated by alternating current, and are, moreover, hum-free in operation.

Another characteristic of the invention consists in the interposition of a thermoelectric cut ofi in the rectifier circuit and a resistance arranged in an auxiliay circuit in such a Way that it, together with the ignition transformer, is switched off by the thermoelectric relay as soon as the latter is switched over into the operating position. The arrangement of a resistance has the advantage that the responsive value of the current to which the thermoelectric cut-oii is attuned may be adjusted, and that the resistance, together with the auxiliary circuit influencing the transformer, is switched off by the thermoelectric relay as soon as it moves into its operating position.

The flame protection device in accordance with the invention is illustrated by way of example in FIGURES 1-3 of the accompanying drawings in which:

FIG. 1 shows schematically a thermoelectrically controlled fully automatic flame protection device with a monitoring relay which is in accordance with the invention additional to a thermoelectric relay.

FIG. 2 shows a flame protection device in operating position, in the form of a wiring diagram, the monitoring relay being combined with the pilot gas valve in a unit assembly and having a common armature.

FIG. 3 shows a detail in the form of a diagram to show the monitoring relay rigidly coupled to the pilot gas valve.

The operation of the device according to the invention is as follows:

On closing switch 1 in FIG. 1 the mains voltage is applied to the contacts 2-3 of a thermostat 4 and to the contacts 5-6 of a thermal cut-off 7, as well as to contacts 8-? of thermoelectric relay 10 and the primary winding of ignition transformer 11, so long as pressure switch 26 in the main circuit and actuated by gas pressure on its diaphragm 27 is closed. The secondary voltage from the ignition transformer 11 is applied to ignition electrode 12 to provide a spark at the front of the pilot jet 13. When switch 1 is closed, the coil 14b of the pilot gas valve 14 is connected to the mains voltage to open the gas conduit to the pilot jet 13 where the gas is ignited by sparks enerated by the secondary winding of transformer 11. When the E.M.F. from the thermocouple element has reached the value required to operate the thermoelectric relay 10, contacts 8-9 are opened and contacts 16-17 closed. Now mains voltage is applied to the coil 18a of normally closed main gas valve 18, provided that contacts 24-25 of an intermediate relay 23, needed only with large magnetic valves and connected in series, are closed, and contacts 31-32 and 33-34 of monitoring relay 30 in circuit with the coil 13a of main gas valve 18 are closed, and the main gas valve opens and is shown to be in its operating position by the lighting of an indicator lamp 19. Gas passing through the main burner 20 is ignited by the pilot flame. As the thermoelectric relay 10 changes over from contacts 8-9 to contacts 16-17, the ignition transformer 11 is switched olf. The flame protection device is then in the operating position.

It is not necessary to describe the functions of the thermostat 4 and the thermal cut-off 7, as these devices are known per se and do not affect the function of the flame protection device as described above.

If for any reason the mains electricity supply fails, the coil 30a of the monitoring relay is no longer energized. Contacts 31-32 and 33-34 are then opened, and the intermediate relay 23 opens contacts 24-25, so that the coil of the main gas valve 18 is deenergized and the valve immediately cuts off the gas supply to burner 20, while the other contacts 35-36 in the primary circuit are closed. The ignition process will be restarted only when the voltage from the thermoelectric element has dropped enough to open contacts 16-17 and close contacts 8-9 of thermoelectric relay 10 to restore mains current after the cause of the supply failure has been removed. Mains current then flows again through the primary winding of ignition transformer 11 and the ignition process described above is repeated.

Interruption of the mains current may also be due to a drop in gas pressure large enough to cause the diaphragm of pressure switch 26 to fall by its own weight and so open switch 26. On restoration of gas pressure the pressure switch 26 is automatically closed again, and the device restarts automatically as already described.

As in FIG. 1, FIG. 2 shows main switch 1 followed by contacts 2-3 of thermostat 4, with transformer 11 connected in series and having its return circuit controlled by thermoelectric relay with contacts 8-9. Voltage from the secondary winding of the transformer is applied to a coiled filament. When the primary circuit is closed, valve 14 is opened by monitoring relay 30 through lost motion connection 14a and gas flows through pilot line 43, pilot gas valve 14, and pilot line 44. The gas is ignited at the wire filament 12 which glows (this arrangement may be replaced by one for generating sparks). When the voltage from the thermocouple element heated by the pilot flame has reached the value required to operate the thermoelectric relay 10', contact pairs 8-9 to one auxiliary circuit are opened and contacts 16-17 to the other auxiliary circuit are closed, so that the mains voltage, as later described in detail, energizes the coil 18a of the main gas valve 18. However, when the mains circuit is closed by main switch 1 and thermostat 4, another circuit is also closed in which among other things are arranged rectifier 56 and coil a of monitoring relay 30 in circuit with thermoelectric relay 10' through its second contact pair 8-9'. The monitoring relay 30 mechanically controls the pilot gas valve 14 either without direct coupling with one common armature as in FIG. 2, or with direct coupling as in FIG. 3. The monitoring relay 30 has two further sets of contacts 31-32 and 33-34. When the coil 30a of monitoring relay 30 is energised, its circuit is closed directly through contacts 31-32 and at the same time the return circuit of main gas valve 18, which is magnetically controlled, is closed through the other contacts 33-34 of monitoring relay 30.

As may also be seen in FIG. 2, the thermal cut off 7 with contact 6 is connected in series on the alternating current side with rectifier 56 and has a parallel circuit through resistance 60 to contact 9 of thermoelectric relay 10.

Starting and operation are as follows: The main switch 1 is closed and thermostat 4 and thermoelectric relay 10' are connected at their respective contacts 2-3, 8-9, and 8-9'. The thermoelectric relay 10' closes the circuit containing the ignition transformer 11. The thermal cut-off 7 in the mains supply is closed by its contact 6. Current flows through rectifier 56, connected with its outlet to the mains return line, and energizes the monitoring relay 30 following it in the same circuit, the return line from monitoring relay 30 to rectifier 56 being closed by the second pair of contacts 8'-9 of the thermoelectric relay 10'. The pilot gas valve controlled by monitoring relay 30 opens the gas Way to the ignition head with thermocouple element 15. Gas from pilot line 43 via opened pilot gas valve 14 and pilot line 44 is ignited by the blowing filament 12' in front of the ignition head and through which the secondary current from the transformer 11 flows. The pilot flame now generates at the hot junction of the thermocouple element 15 a thermoelectric current which switches over the thermoelectric relay 10 as soon as the value necessary to operate it has been reached. Contacts 8-9 and 8-9' are thereby opened respectively disconnecting ignition transformer 11 and the coil 30a of monitor relay 30. Monitor relay coil 30a remains energized however through the holding circuit established by contacts 31 and 32 thereof. Through contacts 16 and 17 of thermoelectric relay 10 and contacts 33 and 34 of monitor relay 30 a circuit is established through the magnetic gas valve coil 18a. Gas passing the main gas valve 18 is now ignited by the pilot flame.

The monitoring relay 30 also serves as a cut-off relay in case of a short interruption of mains current, for example when contacts 2-3 of room thermostat 4 are opened, because the coil of the monitor relay is deenergized and the sets of contacts 31-32 and 33-34 of the monitoring relay 30 are opened and immediately shut off the magnetic main gas valve 18 and pilot gas valve 14. The monitoring relay coil 30a and ignition transformer 11 can only come into circuit again after the voltage from thermocouple element 15 has fallen below the value needed to operate the thermoelectric relay 10' and after the latter has reclosed contacts 8-9.

In FIGURE 1 the purpose of the thermal cut-off 7 is to switch off the ignition transformer 11 and monitoring relay 30 after a predetermined period, for example 30 seconds, during which ignition has been repeatedly unsuccessful. Only after the cause of ditficulty has been eliminated and after resetting thermal cut-off 7 by push button (not shown) can the plant be restarted as above described.

In FIGURE 2, the thermal cut-off 7 is in the line to the rectifier.

Invention is claimed as follows:

1. In an automatic protection device to be connected to electric mains and for a gas burner having a main burner and an electrically operated valve therefor, a pilot burner and an electrically operated valve therefor, and an electrically operated ignition device, the improvement comprising: thermoelectric means mounted to be heated by said pilot burner when the pilot burner is on, said means producing an electric current when heated; a first relay having a coil and normally opened contacts and normally closed contact means, said coil being connected to said thermo-electric means to be energized by said current; a temperature responsive switch; means connecting said switch, said normally closed contact means, said ignition device, and said electric mains in series; means connected to the pilot valve and in series with the switch and mains to supply electricity to the pilot valve; monitor relay means having a coil and two pair of normally opened contacts which are closed upon the actuation of the monitor relay means; means connected in series with said switch and said mains and connecting the normally closed contact means of the first relay and said coil of the monitor relay means in series to actuate the monitor relay means upon the closing of the switch when the normally closed contact means of the first relay are closed, the last means also connecting said coil of the monitor relay means and one of said two pair of normally opened contacts of the monitor relay means in series to hold said monitor relay means in the actuated position, after actuation and until the electric current to said coil of the monitor relay means is interrupted other than by said one said two pair of contacts opening; and means connected in series with said mains and said switch and connected to the normally opened contacts of the first relay, the other pair of normally opened contacts of the monitor relay means and to the main burner valve to open the burner valve upon the switch and contacts closing and to close said valve upon the occurrence of any one of, the failure of electric power in the mains, the opening of the switch, the opening of the normally opened contacts the first relay and the opening of the other pair of contacts of the monitor relay means.

2. In an automatic protection device to be connected to electric mains and for a gas burner having a main burner and an electrically operated valve therefor, a pilot burner and an electrically operated valve therefor, and an electrically operated ignition device, the improvement comprising: thermoelectric means mounted to be heated by said pilot burner when the pilot burner is on, said means producing an electric current when heated; a first relay having a coil, normally opened contacts and normally closed contact means, said coil being connected to said thermoelectric means to be energized by said current; a temperature responsive switch; means connecting said switch, said normally closed contact means, said ignition device, and said electric mains in series; a monitor relay means having a coil and two pair of normally opened contacts which are closed upon the actuation of the monitor relay means; means connected in series with said switch and said mains and connecting the normally closed contact means of the first relay and said coil of the monitor relay means in series to actuate the monitor relay means upon the closing of the switch when the normally closed contact means of the first relay are closed, whereby the coil of the monitor relay means will not be energized when the first relay is energized and said normally closed contact means are opened, the last means also connecting said coil of the monitor relay means and one of said two pair of normally opened contacts of the monitor relay means in series to hold said monitor relay means in the actuated position, after actuation and until the electric current to said coil of the monitor relay means is interrupted other than by said one of said two pair of contacts opening; means connected to the monitor relay means and the pilot valve to open the pilot valve when the coil of the monitor relay means is energized; and means connected in series with said mains and said switch and connected to the normally opened contacts of the first relay, the other pair of normally opened contacts of the monitor relay means and to the main burner valve to open the burner valve upon the switch and contacts closing and to close said valve upon the occurrence of any one of, the failure of electric power in the mains, the opening of the switch, the opening of the normally opened contacts the first relay and the opening of the other pair of contacts of the monitor relay means.

3. In an automatic protection device to be connected to electric mains through a switch and for a gas burner having a main burner and an electrically operated valve therefor, a pilot burner and an electrically operated valve therefor to be opened upon the closing of said switch, and an electrically operated ignition device, the improvement comprising: thermoelectric means mounted to be heated by said pilot burner when the pilot burner is on, said means producing an electric current when heated; a first relay having a coil, normally opened contacts and normally closed contact means, said coil being connected to said thermoelectric means to be energized by said current; means connecting said switch, said normally closed contact means, said ignition device, and said electric meains in series; a monitor relay means having a coil and two pair of normally opened contacts which are closed upon the actuation of the monitor relay means; means connected in series with said switch and said mains and connecting the normally closed contact means of the first relay and said coil of the monitor relay means in series to actuate the monitor relay means upon the closing of the switch when the normally closed contact means of the first relay are closed, the last means also connecting said coil of the monitor relay means and one of said two pair of normally opened contacts of the monitor relay means in series to hold said monitor relay means in the actuated position, after actuation and until the electric current to said coil of the monitor relay means is interrupted other than by said one of said two pair of contacts opening; and means connected in series with said mains and said switch and connected to the normally opened contacts of the first relay, the other pair of normally opened contacts of the monitor relay means and to the main burner valve to open the burner valve upon the switch and contacts closing and to close said valve upon the occurrence of any one of, the failure of electric power in the mains, the opening of the switch, the opening of the normally opened contacts the first relay and the opening of the other pair of contacts of the monitor relay means.

4. In a device as set forth in claim 2, wherein said means connected to the monitor relay means and the pilot valve includes a mechanical connection between the monitor relay means and the pilot valve.

5. In a device as set forth in claim 2, wherein the monitor relay means includes an armature, and said means connected to the monitor relay means and the pilot valve includes a direct coupling between the armature and the pilot valve to operate the pilot valve.

6. In a device as set forth in claim 2, wherein the means connected to operate the monitor relay means and the means connected to open the main burner valve include rectifier means with the monitor relay means and the main burner valve being arranged in the direct current circuit from said rectifier means.

7. In a device as set forth in claim 6, including a thermal cutoif in series with the rectifier means and having a resistance so arranged in an auxiliary circuit that said resistance together with the ignition device is switched off by the first relay when the coil thereof is energized.

References Cited in the file of this patent UNITED STATES PATENTS 2,238,224 Laing Apr. 15, 1941 2,407,438 Newman Sept. 10, 1946 2,471,343 Newman May 24, 1949 2,710,181 Parrett June 7, 1955 2,800,176 Morrison July 23, 1957 2,812,806 Morrison Nov. 12, 1957 2,952,308 Schwank Sept. 13, 1960 

2. IN AN AUTOMATIC PROTECTION DEVICE TO BE CONNECTED TO ELECTRIC MAINS AND FOR A GAS BURNER HAVING A MAIN BURNER AND AN ELECTRICALLY OPERATED VALVE THEREFOR, A PILOT BURNER AND AN ELECTRICALLY OPERATED VALVE THEREFOR, AND AN ELECTRICALLY OPERATED IGNITION DEVICE, THE IMPROVEMENT COMPRISING: THERMOELECTRIC MEANS MOUNTED TO BE HEATED BY SAID PILOT BURNER WHEN THE PILOT BURNER IS ON, SAID MEANS PRODUCING AN ELECTRIC CURRENT WHEN HEATED; A FIRST RELAY HAVING A COIL, NORMALLY OPENED CONTACTS AND NORMALLY CLOSED CONTACT MEANS, SAID COIL BEING CONNECTED TO SAID THERMOELECTRIC MEANS TO BE ENERGIZED BY SAID CURRENT; A TEMPERATURE RESPONSIVE SWITCH; MEANS CONNECTING SAID SWITCH, SAID NORMALLY CLOSED CONTACT MEANS, SAID IGNITION DEVICE, AND SAID ELECTRIC MAINS IN SERIES; A MONITOR RELAY MEANS HAVING A COIL AND TWO PAIR OF NORMALLY OPENED CONTACTS WHICH ARE CLOSED UPON THE ACTUATION OF THE MONITOR RELAY MEANS; MEANS CONNECTED IN SERIES WITH SAID SWITCH AND SAID MAINS AND CONNECTING THE NORMALLY CLOSED CONTACT MEANS OF THE FIRST RELAY AND SAID COIL OF THE MONITOR RELAY MEANS IN SERIES TO ACTUATE THE MONITOR RELAY MEANS UPON THE CLOSING OF THE SWITCH WHEN THE NORMALLY CLOSED CONTACT MEANS OF THE FIRST RELAY ARE CLOSED, WHEREBY THE COIL OF THE MONITOR RELAY MEANS WILL NOT BE ENERGIZED WHEN THE FIRST RELAY IS ENERGIZED AND SAID NORMALLY CLOSED CONTACT MEANS ARE OPENED, THE LAST MEANS ALSO CONNECTING SAID COIL OF THE MONITOR RELAY MEANS AND ONE OF SAID TWO PAIR OF NORMALLY OPENED CONTACTS OF THE MONITOR RELAY MEANS IN SERIES TO HOLD SAID MONITOR RELAY MEANS IN THE ACTUATED POSITION, AFTER ACTUATION AND UNTIL THE ELECTRIC CURRENT TO SAID COIL OF THE MONITOR RELAY MEANS IS INTERRUPTED OTHER THAN BY SAID ONE OF SAID TWO PAIR OF CONTACTS OPENING; MEANS CONNECTED TO THE MONITOR RELAY MEANS AND THE PILOT VALVE TO OPEN THE PILOT VALVE WHEN THE COIL OF THE MONITOR RELAY MEANS IS ENERGIZED; AND MEANS CONNECTED IN SERIES WITH SAID MAINS AND SAID SWITCH AND CONNECTED TO THE NORMALLY OPENED CONTACTS OF THE FIRST RELAY, THE OTHER PAIR OF NORMALLY OPENED CONTACTS OF THE MONITOR RELAY MEANS AND TO THE MAIN BURNER VALVE TO OPEN THE BURNER VALVE UPON THE SWITCH AND CONTACTS CLOSING AND TO CLOSE SAID VALVE UPON THE OCCURRENCE OF ANY ONE OF, THE FAILURE OF ELECTRIC POWER IN THE MAINS, THE OPENING OF THE SWITCH THE OPENING OF THE NORMALLY OPENED CONTACTS THE FIRST RELAY AND THE OPENING OF THE OTHER PAIR OF CONTACTS OF THE MONITOR RELAY MEANS. 